1. Field of the Invention
The present invention relates to a compression apparatus for reducing the volume of solid waste by compression and particularly though not exclusively to a compression apparatus for volume reducing radioactive solid waste at a high pressure.
2. Related Art Statement
In the field of the nuclear power generation and the related fields, radioactive substances produced and solid waste contaminated with radioactive substances are subjected to a volume reduction treatment and then sealingly contained in a container for storage or transportation. In the volume reduction process, it is conventionally made to reduce the volume of a container, such as drum containing radioactive substances, by axially compressing it in a hollow cylindrical mold for preventing radioactive particulates, such as chips, from flying about. However, this prior art uniaxial compression apparatus is disadvantageous in that the circumferential wall of the drum is liable to seize upon the inner cylindrical wall of the hollow cylindrical mold when it expands radially outwards due to axial compression, and in that it is hard to reduce the volume of drums containing various kinds of solid waste so that the compressed drums have a predetermined shape and volume for placing them in new drums.
For reducing disadvantages of the above mentioned uniaxial compression apparatus, one of the inventors has proposed a triaxial compression apparatus for volume reducing solid waste in Japanese Utility Model 18-Month Publication No. 60-190,497 issued on Dec. 17, 1985, In this compression apparatus, a cylindrical waste container is compressed in one radial direction into the shape of an elliptic cylinder, then in another radial direction perpendicular to the one radial direction into a non-cylindrical shape and finally in the axial direction into a volume-reduced cylindrical shape. This triaxial compression apparatus is advantageous in that little seizure of the container is produced during compression, and in that containers, containing various kinds of solid waste, are compressed into a predetermined shape with ease. However, it is more complicated in structure than the uniaxial compression apparatus.